Complex Reorientation Dynamics of Sizable Glass-Formers with Polar Rotors Revealed by Dielectric Spectroscopy

We present the results of dielectric measurements for three sizable glass-formers with identical nonpolar cores linked to various dipole-labeled rotors that shed new light on the picture of reorientation of anisotropic systems with significant moment of inertia revealed by broadband dielectric spectroscopy. The dynamics of sizable glass-formers formed by partially rigid molecular cores linked to small polar rotors in many respects differs from that of typical glass-formers. For instance, the extraordinarily large prefactors (tau(0) > 10(-12) s) in the Vogel-Fulcher-Tammann equation were found. The rich and highly diverse relaxation pattern was governed by the location of a dipole, its ability to rotate freely, and the degree of coupling to the motion of the entire sizable system.

Automated summary

By conducting dielectric measurements on three sizable glass-formers with nonpolar cores linked to dipole-labeled rotors, new insights were gained on the reorientation of anisotropic systems with significant moment of inertia. The dynamics of these glass-formers differ from typical ones, showing extraordinarily large prefactors in the Vogel-Fulcher-Tammann equation, and a rich relaxation pattern controlled by the location and ability of dipoles to rotate freely, as well as their coupling to the movement of the entire system.